There is a great interactive site created by the Smithsonian National Museum of Natural History where students and teachers alike can explore Earth Science. The address is :
I would use this interactive site to create student interest and motivation by letting the students drive. That is to say, I would let the students decide which area of Earth science they would like to begin to explore. To promote the lesson, I would put a few thought provoking questions and/or interesting statements related to Earth science on the board. In the past, I have found that a well worded starter on the board is all the students need to be hooked. For example, I might write the questions “What does ice have in common with quartz?” followed by “Name as many characteristics that they share as you can” on the board. Or I could write a statement such as “Did you know that the two elements that make up table salt (sodium and chlorine), by themselves, can be extremely dangerous?” Or I could simply write “All rocks contain water” and let the students think about how that is possible. Anyways, I would hook the students with something that I believe would interested them and learning more about the topic. Besides, using an interactive site (using technology in general) seems to always be a kid favorite.